劲头 (jìn tóu): enthusiasm; zeal; vigor; strength

Entering the final lap of the race, although he was almost out of energy, hearing his classmates cheering gave him renewed enthusiasm.

Seeing how enthusiastically my younger brother practices piano every day, I was inspired and decided to take up guitar again.

The new intern has a particularly high level of enthusiasm for work, arriving at the office earliest every day and leaving latest.

After working overtime for several days straight, everyone was a bit tired, but at the thought that the project was almost finished, they regained their enthusiasm.